Production of butinediol



Patented Nov. 1, 1949 PRODUCTION OF BUTINEDIOL Thomas E. Londcrgan, Niagara Falls, N. Y., as-

signor to E. I. du Pont de Nemours & Company, Wilmington, Del., a corporation of Delaware No Drawing. Application October 4, 1947, Serial No. 778,024

Claims. (Cl. 260-635) This invention relates to an improved process for the production of 2-butinediol-l,4.

The recently granted patent to Reppe et al., U. S. Patent No. 2,232,867 discloses a process for the production of 2-butlnediol-l,4 by reacting an aqueous solution of formaldehyde with acetylene in the presence of a metal acetylide catalyst selected from the group consisting of copper acetylide, silver acetylide, gold acetylide, and mercury acetylide. By the process of said patcut, it is impossible to obtain a satisfactory yield of the butinediol within a reasonable period of time unless the process is operated at super-atmospheric pressure. On the other hand, when super-atmospheric pressures are used, as suggested in the patent, the process is dangerous by reason of the explosion hazard of acetylene under pressure. The process of the above-said patent is also subject to the objection that the 2-butinediol-l,4 produced contains, as an impurity, small amounts of propargyl alcohol.

It is an object of this invention to provide a process for the production of 2-butinediol-1,4 which will have an excellent yield and may be carried out in a minimum period of time at atmospheric pressure.

It is another object of this invention to provide a process for the production of 2-butinediol- 1,4 which will have an excellent yield and may be carried out in a minimum period of time without objectionable explosion hazard.

It is still another object of this invention to provide a process for the production of 2-butinediol-l,4 which is substantially free from propargyl alcohol.

Other objects of the invention will appear hereafter.

The objects may be accomplished, in general, by reacting a polyoxymethylene glycol containing b tween eight and one hundred formaldehyde uni per molecule with acetylene in a saturated aliphatic organic acid ester having a boiling point between 162 C. and 210 C. and containing not to exceed 5% free water, as a reaction medium. The reaction is carried out in the presence of a metal acetylide taken from the group consisting of copper acetylide, silver acetylide, gold acetyllde, and mercury acetylide, and at a temperature between 60 C. and 150 C.

The above-said polyoxymethylene glycol includes paraformaldehyde, which Staudinger has defined as a mixture of polyoxymethylene glycols containing between eight and one hundred formaldehyde units, as well as similar polymers of formaldehyde which may have a more uniform degree of polymerization. It has been found, in accordance with this invention, that commercial formaldehyde solutions or similar aqueous solutions of formaldehyde cannot be reacted with acetylene at atmospheric pressure to produce a good yield of the butinediol unless the reaction is carried out for a long period of time (a period of two or more days). By the use of paraformaldehyde, orsimilar polyoxymethylene glycol, in a liquid reaction medium composed of a saturated aliphatic organic acid ester having a boiling point between 162 C. and 210 C. and containing not to exceed 5% free water, a good yield can be obtained at atmospheric pressure in a period of two to six hours. Not only is the paraformaldehyde more reactive than formaldehyde but free water in larger quantities than about 5%, as well as. alcohol and hydrocarbons, in the reaction medium, have a decidedinhibiting efl'ect on the reaction. On the other hand, it has been found that polyoxymethylene glycols having more than one hundred formaldehyde units per molecule, 1. e., formaldehyde polymers known as alpha-polyoxymethylene, are not suitable for the production of 2- butinediol-1,4 since they are not sufliciently reactive.

Paraformaldehyde is readily produced by the evaporation of a formaldehyde solution, and the process of this invention may be carried out with paraformaldehyde produced in situ in the reaction medium by passing aqueous formaldehyde solution into the hot reaction medium through which an excess of acetylene is being swept so as to carry off excess water. This procedure must be so controlled that a concentration of more than 5% free water will never be present in the reaction mixture. Paraformaldehyde can also be produced in situ by passing formaldehyde gas into a substantially non-aqueous reaction mixture. Aqueous formaldehyde solutions 162 C. and 210 c. As examples of esters in-' cluded in this class the following may be named: ethylene diacetate, ethylene dipropionate, z-ethyl butyl acetate, 2-ethyl hexyl acetate, octyl acetate, isoamyl butyrate, and isoamyl isovalerate. As above stated, water, alcohol, and hydrocarbons have now been found to inhibit the reaction. The liquid reaction medium must, therefore, contain less than 5% free water or like reaction-inhibiting liquid. The amount of the liquid reaction medium employed is not critical. A suflicient amount should, of course, be used to maintain the reaction mass in a liquid, dissolved or slurry, form. In a batch type process, the liquid reaction medium is preferably employed in an amount between three and twenty times the weight of the polyoxymethylene glycol present in the reaction mass. In a continuous type process, the butinediol may be continuously removed by distillation of the reaction max, and the reaction medium recycled. The 2-butinedial-1,4 produced by the reaction will, unless removed, accumulate in the reaction mass. It has now been found that small amounts of the butinediol will not interiere with the reaction; however, if it is allowed to accumulate until it exceeds about 50%, based on the combined weight of the butinediol and the liquid reaction medium, it will materially interfere with the production of good yields. It is, therefore, preferred that the concentration of the butinediol product in the reaction mass be not allowed to exceed 50% based on the combined weight of the butinediol and the liquid reaction medium employed. This may be readily accomplished by discontinuing the reaction or by adding additional liquid reaction medium in a batch type process, or by continuous removal of the butinediol from the reaction medium by distillation of the reaction mass and recycling of the reaction-medium, or by continuous addition of reaction medium in a continuous type process. 1

The metal acetylide catalyst, i. e., copper acetylide, silver acetylide, gold acetylide, or mercury acetylide, or any mixture or combination thereof, 'may be prepared from aqueous metal salt solutions asdisclosed in the abovesaid patent to Reppe et al. The metal acetylide should be contained on a catalyst support such as fullers earth, infusorial earth, activated carbon, silica gel, or the like. The preferred metal acetylide catalyst material for use in accordance with this invention is one produced by mixing particles of a catalyst support having a size not to exceed 300-mesh with an aqueous solution of a metal salt and precipitating the metal acetylide on the particles of catalyst support by passing acetylene through the said mixture. The quantity of metal acetylide. precipitated on the particles of support should not exceed 20%, by weight, of the final dry catalyst. This particular catalyst and the method of producing the same is the subject of copending patent application Serial No. 561,150, filed October 30, 1944, and now abandoned. The amount of catalyst present in the reaction mass may be varied between wide limits, for example, the presence of 1% to ditlons of operation, it is preferred to carry out the reaction at a temperature between 115 C. and 125' O.

The following detailed examples are given to 7 illustrate certain preferred methods for carrying out the present invention. it being understood, of course, that the precise details set forth in these examples are to be taken as illustrative and not limitative of the invention.

Example I 'two gram-molecular weights of CHaO) were added. and dry acetylene was passed in with agitation at a rate only slightly in excess of the rate of acetylene absorption. Additional Daraformaldehyde was added after one-half moi of acetylene had been absorbed and addition was continued until a total of 315 grams or equivalent to ten gram-molecular weights of CHaO' as paraformaldehyde had been added. when acetylene absorption was complete, the reaction mixture was filtered and the catalyst washed with ethylene diacetate. these washings being added to the filtrate. The 2-butinediol-l,4 was isolated from the filtered reaction mixture by vacuum distillation, distilling at 120 C. to 145 C. at 7 mm. On redistillation, a substantially pure product, boiling at 130 C.v to 135 C. at '7 mm., was secured. A yield of 340 grams or 79% theoretical was obtained. The butinediol produced by the above reaction was free from propargyl alcohol.

' Example II 300-mesh or finer, active carbon) and 63 grams of paraformaldehyde.

heated to 125 C. and acetylene was bubbled I The mixture was then through it with constant agitation at atmospheric pressure. Approximately of the theoretical acetylene was absorbed in two hours and the reaction was substantially complete in three hours. The reaction mixture was filtered, the catalyst being washed with a small quantity of ethylene dipropionate and the 2-butinediol-L4 recovered from the filtrate by vacuum distillation. The

yield was approximately 69 grams or 80% theoretical. The reaction product was substantially free from propargyl alcohol.

Example HI Two mols of formaldehyde in the form of 60 grams of alpha polyoxymethylene containing 99.9% formaldehyde were added to 400 grams of ethylene diacetate containing 16 grams of copper acetylide on 80 grams of powdered, substantially pure, neutral activated carbon. Acetylene was passed through the resultant mixture with agitation foron'e'hour at C. with absorption of only 2.5 liters; the temperature was then a raised to C., but only 1.3 liters were absorbed in one-half hour. This is only 25% to 27% of the quantity of acetylene which would be absorbed by paraformaldehyde under similar circumstances. This example illustrates that alphapolyoxymethylene is not sufliciently reactive to be a satisfactory reactant for use in accordance with the present invention.

Example IV The process of Example I was repeated except that 2-ethyl butyl acetate was sub tituted for the ethylene diacetate in equivalent amount. The yield of 2-butinediol-1,4 was 71% propargyl alcohol could be detected.

Example V The process of Example I was repeated except that octyl acetate was substituted for the ethylene diacetate in equivalent amount. The yield of 12-butinediol-L4 was about 10% and no propargyl alcohol could be detected.

In all of the above examples, the acetylene was passed into the solvent containing formaldehyde,

' or formaldehyde polymer, at atmospheric pressure.

By the process of this invention, 2-butinediol-1,4 is readily produced at atmospheric pressure'and, therefore, without the menace of explosion such as is present in the handling or maintaining of the acetylene at pressures above atmospheric. The reaction takes place rapidly with excellent yields without the production of propargyl alcohol, and the butinediol can be readily isolated from the solvents employed since it is substantially free from water.

Throughout the [specification and claims, proportions and percentages refer to proportions and percentages by weight unless otherwise specifled.

Since it is obvious that many changes and modifications can be made in the above-described details without departing from the nature and spirit of the invention, it is to be understood that the invention is not to be limited to the abovesaid details except as set forth in the appended claims.

What is claimed is: e

1. A process for the production of 2-butinedid-1,4 which comprises reacting, at a temperature between 60 C. and 150 C., a polyoxymethylene glycol containing between eight and one hundred formaldehyde units per molecule with acetylene in a saturated aliphatic organic acid ester having a boiling point of between 162 C. and 210 C. and which does not contain to exceed 5%, by weight, free water and which is present in sufficient amount to maintain the reaction mass in liquid form, said reaction being carried out in the presence of a metal acetylide catalyst taken from the group consisting of copper acetylide, silver acetylide, gold acetylide, and mercury acetylide.

2. A process for the production of 2-butinedial-1,4 which comprises reacting, at a temperature between 115 C. and 125 0., a polyoxymethylene glycol containing between eight and one hundred formaldehyde units per molecule with acetylene in a saturated aliphatic organic acid ester having a boiling point of between 162 C. and 210 C. and which does not contain to exceed 5%, by weight, free water and which is present in suflicient amount to maintain the reaction mass in liquid form, said reaction being carried out in the presence of a metal acetylide catalyst taken from the group consisting a copper acetylide, silver acetylide, gold acetylide, and mercury acetylide.

3. A process for the production of z-butinediol- 1,4 which comprises reacting, at a temperature between 60 C. and C., a polyoxymethylene glycol containing between eight and one hundred formaldehyde units per molecule with acetylene in ethylene diacetate which does not contain to exceed 5%, by weight, free water and which is present in sufllcient amount to maintain the reaction mass in liquid form, said reaction being carried out in the presence of a metal acetylide catalyst taken from the group consisting of copper acetylide, silver acetylide, gold acetylide, and mercury acetylide.

4. A process for the production of 2-butinediol- 1,4 which comprises reacting, at a temperature between 60 C. and 150 C., a polyoxymethylene glycol containing between eight and one hundred formaldehyde units per molecule with acetylene in ethylene dipropionate which does not contain to exceed 5%, by weight, free water and which is present in sufllcient amount to maintain the reaction mass in liquid form, said reaction being carried out in the presence of a metal acetylide catalyst taken from the group consisting of copper acetylide, silver acetylide,

gold acetylide, and mercury acetylide.

5. A process for the production of 2-butinediol- 1,4 which comprises reacting, at a temperature between 60 C. and 150 C., a. polyoxymethylene glycol containing between eight and one hundred formaldehyde units per molecule with acetylene in 2-ethylbuty1 acetate which does not contain to exceed 5%, by weight, free water and which is present in suillcient amount to maintain the reaction mass in liquid form, said reaction being carried out in the presence of a metal acetylide catalyst taken from the group consisting of copper acetylide, silver acetylide, gold acetylide, and mercury acetylide. I

THOMAS E. LDNDERGAN.

REFERENCES CITED The following references are of record in the file of this patent: 

